<template>
  <transition name="sidebar-toggle-fade">
    <a class="sidebar-toggle" data-toggle="push-menu" role="button" v-show="visible" :title="text" :style="{bottom: bottom + 'px'}">
      <i class="fa fa-bars"></i><span>&nbsp;&nbsp;{{text}}</span>
    </a>
  </transition>
</template>

<script>
export default {
  name: "SidebarToggle",
  props: {
    text: {
      type: String,
      default: '折叠边栏',
    },
    visibleOffset: {
      type: [String, Number],
      default: 600,
    },
    bottom: {
      type: Number,
      default: 10,
    },
  },
  data() {
    return {
      visible: false,
    };
  },
  created() {
    window.addEventListener("scroll", this.catchScroll);
  },
  beforeDestroy() {
    window.removeEventListener("scroll", this.catchScroll);
  },
  methods: {
    catchScroll() {
      this.visible = window.pageYOffset > parseInt(this.visibleOffset);
    },
  },
};
</script>

<style lang="less" scoped>
.sidebar-toggle-fade-enter-active,
.sidebar-toggle-fade-leave-active {
  transition: opacity 0.7s;
}
.sidebar-toggle-fade-enter,
.sidebar-toggle-fade-leave-to {
  opacity: 0;
}

.sidebar-toggle {
  position: fixed;
  left: 0;
  width: 160px;
  color: #b8c7ce;
  text-align: center;
  line-height: 30px;
  background-color: transparent;
  border-radius: 3px;
  z-index: 1000;
  cursor: pointer;

  &:hover {
    color: #fff;
  }
}

.sidebar-collapse .sidebar-toggle {
  left: 5px;
  width: 40px;

  span {
    display: none;
  }
}
</style>